Stay bolt construction



A. W. BRUCE Jan. 3, I933.

STAY BOLT CONSTRUCTION Filed March 20, 1931 TOR WBmce 6' v/ NEY INVEN fmd ATT - FIGZ? Patented Jan. 3, 1933 ST T5 l id-Ball? ALFRED W. BRUCE, OF NEW YORK, N. Y.

STAY BOLT CONSTRUCTION Application filed March 20,

This invention relates to improvements in stay bolt constructions and particularly to a stay bolt construction especially designed for use in certain parts of a locomotive boiler.

In certain types of locomotives, such as the Garratt type, the fire box is set down between the side members of its supporting frame and the outer ends of the stay bolts employed at this location are thereby rendered entirely inaccessible. It is well known in locomotive practice that due to the relative movement between the shell sheet and the fire box sheet, caused by varying temperatures and pressures, stay bolts frequently break or become defective. In those types of locomotives where the fire box is so positioned between the side members of their supporting frame that the outer ends of. the stay bolts are inaccessible, the removal and replacement of damaged bolts of the usual type and construction, with their outer ends riveted over, necessitates the expensive operation of removing the entire boiler.

The object of the present invention is to provide a stay bolt construction particularly adapted for use at locations in a locomotive boiler where the outer ends of the bolts are inaccessible, which construction will permit the easy renewal of broken or damaged bolts. Other objects and advantages achieved by the present invention. will be apparent from the following description.

The i vention is illustrated in the accompanying drawing in which Figure 1 is a partial sectional view of a stay bolt construction embodying the present invention, the stay bolt being shown in elevation; nig. 2 is a sectional view of a part of a modification of the construction illustrated in Figure 1; and Fig. 3 is a fragmentary vertical sectional view of the fire box section of a locomotive boiler, showing a side frame adjacent there to, with the staybolt construction of the present invention applied to said section.

In the practice of the invention referring descriptively to the specific embodiments thereof which have been selected for exemplification herein, the locomotive boiler fire box, or structure to which the stay bolt is applied, comprises an inner wall or fire box sheet 1,

1931. Serial No. 523,961.

and an outer wall or shell sheet 2, spaced from the inner wall.

The stay bolt 3 is of the general rigid type, is threaded at its ends 4; and 5, and is provided with a tell-tale hole 6, longitudinally formed therein and opening at its opposite ends. The walls 1 and 2, are tapped out or threaded to receive the threaded ends of the stay bolt 3, wl h is screwed into position therein, the outer end l, extending through the threaded opening 7, in the wall 2, and the inner end 5, being sec rely engaged in the threaded opening 8, of the wall -1. Insomuch as the end l, of the bolt by reason of the aforedescribed location is inaccessible, the same is not riveted over or welded to the sheet 2, as in usual prac tice. In order to prevent leakage, however, at this connection, a cap 9, is provided around the outside of said end l and is welded as indicat d at 10, to the wall When the bolt has been inserted in position (as shown in Fig. 1) the inner end of the same is riveted over in the usual manner, providing a head 11. In this construction. any pressure caused by leakage through the fit of the end 4, in the opening 7, is immediately relieved through the tell-tale hole 6 so that no pressure can be built up within the cap.

The construction illustrated in Fig. 2 is identical with that illustrated in Fig. 1, except that in the latter case, the tell-tale hole (in is only partially drilled through the bolt 3a, opening only at its inner end, and serves only the-usual purpose of permitting passage of water therethrough when the bolt becomes damaged or broken.

A specific application of the invention is illustrated in Fig. 3. Here a portion of a fire box section of a locomotive boiler, indicated generally by the numeral 12, is shown with a locomotive side frame member 13 disposed adjacent thereto, as such structure is arranged in certain types of locomotives, for instance, the Garrett type. It will be appar out that the space between the shell sheet 2 and the side frame member 13 is so limited as to render the outer ends of the stay bolts inaccessible for purposes of removing or repairing the staybolt structure. A mud ring 14 is provided between the lower ends of the fire box sheet 1 and shell sheet 2, in the usual manner, and staybolts 6 are passed through i said sheets with caps 9 provided around the outer ends 4 of the bolts, and the inner ends are riveted over providing heads 11, as hereinbefore described.

To remove the stay bolt of the instant invention the same is drilled out of the fire box sheet 1, a square drift is driven into the telltale hole, and the staybolt is backed out from the shell sheet and allowed to drop down onto the mud ring, from which the same may be removed throughwash out plug holes. A new stay vbolt may be then inserted in the usual manner.

It will thus be seen that by the present invention a stay bolt construction has been provided which, while rendering the rigid stay bolt'and shell sheet fits leak proof, in such locations as are inaccessible for heading over the bolt end on the outside of the shell sheet in accordance with usual practice, also permits the bolt to be readily and easily removed for replacement. i

The invention claimed and desired to be secured by Letters Patent is:

' 1. In a locomotive boiler having an inner the box sheet and an outer shell sheet, said shell sheet being so positioned wit-h respect to another part of the'locomotive structure as to render the space therebetween of a breadth insuflicient to permit the attachment of a cap to the sheet or the application or removal of a staybolt from the outside of the boiler after said boiler has been mounted in position, a staybolt assembly comprising a rigid staybolt,

the ends of which are threaded into threaded openings in said boiler sheets, one end ofsaid st'aybolt extending at least to the outer surface of said shell sheet, said rigid staybolt being replaceable from the inside of said boiler; and a hollow leak-proof cap attached over the opening on the outside of said shell sheet prior to the initial assembly of the boiler into position on said locomotive.

2. Thestructure according to claim 1 in which the rigid staybolt is provided with a passageway longitudinally formed therein throughout its length and opening at its ends.

3. The structure according to claim 1 in which the inner end of the rigid staybolt is riveted over the said inner sheet.

ALFRED W, BRUCE. 

